Blue Doors (also known as Blue Hatches) are doors that can be opened by any weapon. They are found in every Metroid game except Metroid II: Return of Samus, Metroid Fusion (replaced by a Blue Hatch) and Metroid: Other M (replaced by automatically opening doors). The blue color is actually the color of a force field covering the door. After shooting a blue-colored door, the energy covering it will disrupt and peel off or dissipate, depending on the model. The main purpose of the energy covering the blue doors is to avoid accidental/unintentional entries to rooms by wild creatures surrounding the area. This blocks off a large quantity of bioforms from access since most of them cannot manipulate weapons or simply don't have the means to produce an energy-based projectile.
In Metroid Prime 2: Echoes, the logic behind this design of door is explained by using the Scan Visor on a regular Blue Door. The extensive explanation is not given when scanning a black, white, or 'grey' door, instead, it only informs Samus of what types of weapons energy can interact with the field on those doors.
In Metroid Prime 3: Corruption, by scanning a Blue Door on Elysia (once inhabited by the Chozo), it is revealed that since the discovery of said planet, the Galactic Federation used the model of the Elysian blue door as a basis to all currently existing doors found throughout the galaxy on planets, ships, and stations under Federation control.
Metroid: Samus Returns instead uses yellow-colored doors, but nonetheless retain the same function as Blue Doors.
Super Metroid manualEdit
"These doors can be opened by Beams or Bombs."
Metroid: Zero Mission manualEdit
"These hatches can be opened with any of Samus' weapons."
Metroid Prime 2: Echoes temporary scanEdit
"This is a powered door system. Low-level energy shield on door to prevent activation by local creatures. Weapon fire of any type will disrupt the shield and open the door."
Metroid Prime 3: Corruption Logbook entriesEdit
Galactic Federation Blue Door
Galactic Federation Door
Weapon fire can disrupt the energy shield and open the door.
All Federation doors are designed with a low-level energy shield to prevent accidental activation. Shooting the energy shield will activate and open the door. Blue-colored energy shields may be disrupted by weapon fire of any type.
Bryyo Blue Door
This heavy stone door contains a low-level energy shield that can be disrupted by any weapon.
Bryyo doors are carved from heavy stone native to the planet. Each door has been designed with a low-level energy shield. Shooting the shield with any weapon will open the door.
SkyTown Blue Door
Door has low-level energy shield.
Any weapon fire can disrupt the shield and open the door.
All SkyTown doors contain a low-level energy shield behind their ornate carvings. Shooting the energy shield will activate and open the door. The centuries-old design has served as a blueprint for what is now standard across all planets. Blue-colored energy shields can be opened with any weapon.
- In a collection of Scan Visor panels in Metroid Prime, there appears to be an unused scan of a Blue Door that heavily resembles the Super Metroid sprites. Doors are unscannable in Prime, except for the doors on the Frigate Orpheon when Samus first enters it. When Samus scans the doors, the scan will tell Samus which room the door leads to. The reason for this is unknown, and no other doors have similar scans.
- In Super Metroid, even though Blue Doors can be opened with any weapon, they don't open with Power Bombs. However, in the game's coding, it appears there is a function that allows Blue Doors to be opened with Power Bombs, as this is seen when using the Super Metroid Integrated Level Editor (SMILE), the game's level editor.
- The key of the Corruption map calls Blue Doors "Power Beam Doors" despite the fact that they can be opened with anything.
- The doors on Elysia and Tallon IV bear a striking resemblance to each other, likely because both areas were first colonized by the Chozo.
Blue doors often vary in size, shape and appearance, as demonstrated below.